This invention relates generally to bottling machines and more specifically it relates to a filling unit for use in a counterpressure bottling machine, the filling unit operating without filling pipe and using siphon closure means for limiting the level of charge in the bottle, the siphon closure means including a stopper bell cooperating with an annular siphon channel in the discharging channel for the liquid, the stopper bell having on its upper part apertures for intercepting pulp particles from the liquid.
Filling units of this type are used chiefly for discharging CO.sub.2 -containing liquids that are discharged from a rotary pressure tank of the bottling machine into a bottle connected to the unit. Before initiating the proper filling operation, the pressure between the bottle and the pressure tank is first equalized so that the liquid is discharged in the bottle by the effect of gravity. The gas contained in the bottle is forced by the liquid to return in the tank. For the gas return serves a gas return pipe projecting into the bottle to a level corresponding to the desired charge level and as soon as the liquid discharge in the bottle reaches the opening of the gas return pipe the discharging process is automatically limited because the exchange of the gas for the liquid no longer takes place. A disadvantage of prior-art valves of this kind is in the danger that a quantity of gas occurring above the liquid level in the bottle may bubble up and cause an additional discharge of the liquid above the valve seat in the liquid discharging channel. To avoid this disadvantage, it has been devised to make the valve seat in the form of a siphon including a stopper bell that has its lower rim portion immersed in the sealing liquid contained in an annular siphon channel. This arrangement reduces slightly the efficiency of the filling unit. In order to avoid this disadvantage, a plurality of small apertures have been made in the upper part of the stopper bell above the bell-shaped jacket immersed in the sealing liquid so that these small apertures increase the effective cross-section of the discharging passage during the filling or discharging process. Nonetheless, it has proved that despite of this increase of the cross-sectional area of the liquid discharging channel by means of such additional apertures no substantial increase of the efficiency of the filling unit has been achieved because especially in fluid pulp containing liquids the small apertures became clogged with the pulp fibers and the effect of these apertures is lost.